摘要
硬玉(NaAlSi2O6)及其在极端条件下的行为在地质学和宝石学中有极高的研究价值。考虑到现有单一检测条件的局限,本文综合了多种实验检测手段和理论计算方法对硬玉晶体及其熔体和玻璃的结构以及铝配位数进行了研究。对硬玉晶体热熔过程进行了高温原位拉曼光谱测定,结合第一性原理理论计算方法,得到了硬玉结构和铝配位数的变化及其相应的谱学特征。结合量子化学从头计算对熔体结构进行解析。研究表明:硬玉晶体结构单一且铝全部为六配位,1 293K时大量六配位铝转变为四配位,熔体中四配位铝占主导,其中硅(铝)氧四面体以多元环连接成架状结构。熔体冷却过程中伴随着五配位铝的生成,并呈现分相趋势。
Comprehensive experimental as well as theoretical methods were applied to investigate the structure evolution of jade- ite in the hot-melt process, especially on the variation of aluminium coordination number. In-situ high temperature Raman spec- troscopic technique was used to record the characteristic Raman spectra of jadeite and its melt with the increasing temperature, consequently, density function theory and ab initio calculation methods were applied to analyze the related micro-structures and aluminium coordination number and simulate the Raman spectra. Results showed that aluminum in jadeite crystal is all six-fold and would transform into four-fold coordination at 1 293K while jadeite being melting. Aluminum is prominently in four-fold co- ordination in the melt, in which TO4 （T=Si, Al） connects to each other as the network of multiple rings. Five-fold coordinated aluminum emerges and it appears the trend of phase separation while the melt transformed into glass by the processing of fast cooling.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2013年第10期2705-2710,共6页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金重点项目(50932005)
国家自然科学基金项目(20973107,40973046)
上海市科委科技基金项目(12520709200)资助
关键词
硬玉
高温熔体
铝配位数
拉曼光谱
核磁共振
Jadeite
High temperature melt
Aluminum coordination
Raman spectroscopy
NMR spectroscopy
